The first investigation in this series was a study of the response of otolith neurons to static tilts. This work was followed by a study of the otolith neurons to centrifugal force which are precisely controlled in magnitude and time course. To date only trapezoidal stimuli have been employed. Preliminary results suggest that the response asymmetry characterizing otolith neurons is larger than was estimated from static-tilt experiments. This observation, if confirmed, is important for several reasons. First, the asymmetry may provide a clue to the mechanisms of hair-cell action. Second, it may provide an explanation of the relation seen between the resting discharge and sensitivity of peripheral vestibular neurons. And third, an understanding of response nonlinearities is necessary if the results of linear-system analysis is to be interpreted correctly. The preliminary observations have confirmed that the otolith neurons show adaptation to maintain stimuli, the degree of adaptation exhibited by any particular neuron being related to its regularity of resting discharge.